Expandable structure

ABSTRACT

An expandable structure is disclosed herein in the form of a trailer. The trailer is provided with an extensible base frame and collapsible shells which, in addition to being vertically expandable, are extendible with the base frame. A means is provided for extending the secondary frame means along with a means for adjustably positioning a roof assembly with respect to the shells and to expand the shells.

United States Patent [72] Inventor Walter S. llojka 5300 W. 135th St., Midlothian, lll. 6041415 [21] Appl.1 1o. 834,715 [22] Filed June 19 1969 [45] Patented Aug. 3,197]

[54] EXPANDABLE STRUCTURE 9 Claims, 16 Drawing Figs.

{52] U.S. Cl 52/64, 296/23 C, 296/27 [51] Int. Cl 1360 3/34, E04b 1/344 [50] Field olSearch 52/67,64, 66; 296/23 F, 23, 23 C, 26, 27,23 G

[56] References Cited UNITED STATES PATENTS 2,561,921 7/1951 Guillot 296/23.3

2,704,223 3/1955 Houdart 52/67 X 2,732,251 1/1956 Meaker 52/67 X 2,842,972 7/1958 Houdart 296/23.3

3,429,608 2/1969 Farnum 296/27 3,352,596 11/1967 Escoto 52/66 FOREIGN PATENTS I 882,258 1961 Great Britain 296/26 Primary Examiner-John E. Murtagh Atrorney- Evan D. Roberts ABSTRACT: An expandable structure is disclosed herein in the form of a trailer. The trailer is provided with an extensible base frame and collapsible shells which, in addition to being vertically expandable, are extendible with the base frame. A means is provided for extending the secondary frame means along with a means for adjustably positioning a roof assembly with respect to the shells and to expand the shells.

pmmmue 3191; 3,596,416

SHEET 1 BF 3 INVENTOR WALTER S. HOJKA ATTORNEY EXPANDABLE STRUCTURE SUMMARY OF THE INVENTION This invention relates to a structure which is expandable in both the horizontal and vertical directions. A base frame assembly having a primary frame is provided with secondary frame means horizontally extendible therefrom. A shell means is secured to one or more of the secondary frame means, and the shell means may be expanded vertically. Thus, the base frame assembly and the shell means provide a structure which is expandable in both the horizontal and vertical directions. A vertically adjustable roof assembly provides: a cover for the shell means when the shell means is collapsed or vertically expanded; means for expanding the shells vertically; and a substantially horizontal covering enclosure for the space vacated by the shells when the shells are extended horizontally with the secondary frame means, to enclose the space between the shell means when same is so extended.

It is an object of this invention to provide an expandable structure which may be utilized in the form of a trailer and which when collapsed, will provide a small and low lateral cross section configuration to facilitate safety and convenience in addition to minimizing wind resistance for operation on the highway.

Another object of this invention is to provide a structure which may be expandable to various extents and forms rather than simply being either expanded or collapsed, and thereby, provide an expandable structure which may be expanded according to the space needs and requirements of the individuals which will beutilizing same.

A further object of this invention is to provide an expandable structure which may be expanded and collapsed by a single individual entirely without assistance from other persons.

A still further object of this invention is to provide an expandable structure which is capable of having the lower half of its expanded height substantially completely free to have furniture or other articles permanently positioned therein without in any way, obstructing or interfering with the expandable nature of the structures of the invention.

An additional object of this invention is to provide an expandable structure wherein partitions may be provided between the floor and ceiling of the structure when same is expanded, and without interfering with the furniture or other objects positioned in the lower half of the expanded structure and without interfering with either partial or complete expansion of the structure.

A further object of the invention is to provide an expandable structure having an adjustably positionable roof assembly which will provide a roof for the structure independent of the extent or degree of the expanded nature of the rest of the structure and which will provide a means for expanding the expandable shell structures thereof.

Other advantages and novel aspects of this invention will become apparent upon examination of the following detailed description, in conjunction with the accompanying drawings wherein:

FIG. 1 is a perspective view of the expandable structure of this invention shown in the form of a trailer and in the fully collapsed condition for highway travel;

FIG. 2 is a perspective view of the expandable structure of this invention illustrated in the form of a trailer with only the shell structures thereof expanded vertically to illustrate an intermediate expanded form of the invention;

FIG. 3 is a perspective view of the expandable structure of this invention showing the base frame assembly fully extended and the structure fully vertically expanded illustrating the fully expanded form of the structure of this invention;

FIG. 4 is an end elevation view of the expandable structure of this invention with the structure in the fully collapsed position as shown in FIGS. 1 and 12;

FIG. 5 is an end plan view of the expandable structure of this invention with the structure in the intermediate condition of expansion as shown in FIG. 13;

FIG. 6 is an end elevation view of the expandable structure of this invention with the shells thereof fully vertically expanded and with the roof assembly in its uppermost position;

FIG. 7 is an end elevation view of the expandable structure of this invention with the shells fully vertically expanded and the roof assembly lowered into position thereon;

FIG. 8 is a top plan view of the base frame assembly'of this invention showing the secondary frame means in retracted as well as intermediate and extended positions;

FIG. 9 is a partial sectional view taken along line 9-9 of FIG. 8 showing the secondary frame extending means with the secondary frame in the retracted nonextended position;

FIG. 10 is a partial sectional view taken along line 9-9 of FIG. 8 showing the secondary frame in the partially extended position;

FIG. 11 is a sectional view taken along line 11-11 of FIG. 8 showing a roller and general support for the secondary frame on the primary frame;

FIG. 12 is a side elevation view of the expandable structure of this invention showing the structure in the fully collapsed condition as also shown in FIGS. 1 and 4;

FIG. 13 is a side elevation view of the expandable structure of this invention showing the frame and shell structures in the partial extended and vertically expanded condition as illustrated in FIG. 5;

FIG. 14 is a section view taken along line 14-14 of FIG. 3 of the expandable structure of this invention showing the roof assembly in position and the physical relationship of retractable partitions provided by the roof assembly and the permanent structures possible in the lower shell position;

FIG. 15 is a partial enlarged view taken along line 15-15 of FIG. 7 showing the interrelationship between the roof assembly and the vertically expanded shells; and

FIG. 16 is a partial enlarged sectional view taken along line 16-16 of FIG. 14 showing the longitudinal interrelationship between the roof assembly and the fully expanded shell means.

The expandable structure disclosed in the figures for the purpose of illustrating and describing this invention and generally designated by the numeral 10 includes, among other things, a base frame assembly generally designated by the numeral 11, shell means generally designated by the numeral 12, and a roof assembly generally designated by the numeral 13.

The base frame 11 is provided with a primary frame generally designated by the numeral 15 having a secondary frame means generally designated by the numeral 16 which is extendible from the primary frame 15.

The primary frame 15 is provided with longitudinal frame rails 17 having longitudinally spaced and laterally extending parallel tubes 18 secured thereto in pairs. A tongue platform 19 is provided on the front of the primary frame 15 and a similar step platform 20 is provided on the rear of the primary frame 15. The primary frame 15 may be provided with any usual wheel carriage assembly 21 (FIGS. 1, 2 and 12) to facilitate transportation thereof. However, inasmuch as the wheel carriage assembly 21 does not in; any way form a part of the invention due to the fact that this invention may be transported on a separate vehicle if desired, the carriage 21 is only generally and incidentally illustrated.

The general secondary frame means 16 as illustrated, in-

cludes a pair of secondary frames, generally designated by the numeral 25, that are adjustably extendiible from opposite sides of the primary frame 15. The secondary frames 25 each include extension rack bars 26 secured to an edge rail 27 and extending laterally in complemental telescoping relation with respective parallel tubes 18 of the primary frame 15 for movement therein to allow the secondary frames 25 to be extended from the primary frame 15 as shown (FIG. 8). In particular, the extension rack bars 26 are slidably positioned on vertical and horizontal rollers 28 that are rotatably mounted on shafts 29 (FIGS. 9-11), secured to the rack bars 26 within recesses 30. The rollers 28 are supported on inner surfaces 31 of the parallel tubes to facilitate the movement of the rack bars 26 within the tubes 18.

A secondary-frame-extending means generally designated by the numeral 35 (FIGS. 9 and I) is provided for adjustably moving or extending the secondary frames 25 with respect to the primary frame 15. The secondary-frame-extending means 35 includes generally rack teeth 36 on the underside of each of the rack bars 26 of the secondary frame 16, rack gears 37 mounted on two shafts 38 which are respectively rotatably mounted in bearings 40 on the frame rails 17 and tubes 18 on the right and left sides (FIG. 8) of the base frame 11 with gear teeth 39 in driving-meshing engagement with the rack teeth 36 of the respective rack bars 26. It should be noted that there is a set of rack gears 37 for each of the secondary frames 25 whereby respective rotation of either the right shaft 38 or the left shaft 38 will provide a driving reaction with the respective rack teeth 36 of the right or left rack bars 26.

Cranks 41 or other similar means are provided for selectively and respectively rotating the right and left shafts 38 to rotate the gears 37 which in turn will cause the rack bars 26 of the secondary frame 25 to move within the tubes 18. In regard to the right secondary frame 25 (FIG. 8), clockwise rotation of the gears 37 of the secondary-frame-extending means (FIGS. 9 and on the right side will cause the extension of the right secondary frame 25 to the right by moving the rack bars 26 thereof to the right, while similar counterclockwise rotation of the left gears 37 will cause the retraction of the left rack bars 26 of the left secondary frame means 25 to the left within the tubes 18.

In regard to the left secondary frame 25 (FIG. 8), counterclockwise rotation of the gears 37 of the secondary-frame-extending means (FIGS. 9 and 10) on the left side will cause the extension of the left secondary frame 25 to the left by moving the rack bars 26 thereof to the left, while similar clockwise rotation of the left gears 37 will cause the retraction of the left rack bars 26 of the left secondary frame means 25 to the right within the tubes 18.

Thus, by appropriately rotating the left or right set of gears 37 by the cranks 41 or similar means, the left or right secondary frames 25 of the secondary frame means 16 can be horizontally located in any extended position with respect to the base frame 11, from the fully extended position 42 (FIGS. 3 and 8) to the fully retracted position (FIGS. 1, 2, 4, 8 and 9), and including an intermediate position 43 (FIGS. 8 and 10).

The. expandable shell means 12, as illustrated herein, is shown as two shell means 12, each of which includes a lower shell portion 45 and an expandable upper shell portion 46.

Each lower shell portion 45 (FIGS. 2, 3, 5-7, 9 and I0) is provided with a floor panel 47 (FIGS. 9 and I0) secured at the outer end thereof to the respective edge rail 27 thereof, and the floor panel is supported inwardly therefrom on a floor panel 48 (FIGS. 8-10) secured to the base frame 15, and forming a part thereof. Each lower shell portion 45 has a vertical wall panel 49 extending upwardly and longitudinally along a respective secondary frame 16 adjacent the edge rails 27 thereof, and vertical wall end panels 50 (FIGS. 5-7, 13 and 14) are secured to the wall panel 49 and floor panel 47. Although the floor and end panels 47 and 50 are desirable, the wall panel 49 comprises the basic lower shell portion 45 which will be moved or extended outwardly with the movement or outward extension of the respective secondary frame 16 to which it is respectively attached. 7

' The shell means 12 also includes the upper shell portion 46 which has a roof panel 55 secured to one edge of a wall panel 57 at a dihedral 58. The wall panei 56 in turn is pivotally secured by hinges 59 to the vertical wall panel 56 of the lower shell portion 45 along the top of the wall panel 49 of the lower shell portion 45. The roof and wall panels 55 and S6 of the upper shell portions 46 are longer than the respective wall panels 49 of the lower shell portion 45 (FIGS. 2-4, 13 and 14) so that end panels 59 can be provided on the roof and wall panels 55 and 56 of the upper shell portions 46, and so that the end panels 59 ofthe upper shell portions 46 will clear the end panels 50 of the respective lower shell portions 45 when the upper shell portions 46 are pivoted about the hinges 58 (FIGS.

5 and 13). The roof and wall panels 55 and 56 of the upper shell portions 46 thus respectively pivotally connected to the vertical wall panels 49 of the lower shell portions 45 provide upper shell portions 46 which are pivotable from a collapsed position (FIGS. 1, 4 and 12), through an intermediate position (FIG. 5 and 13) to a fully expanded up position (FIGS. 2, 3 6, 7 and 14). The end panels 59 secured to the roof and wall panels 55 and 56 will thereby clear the end panels 50 of the lower shell portions 45 when the upper shell portions 46 are pivoted with respect to the respective lower shell portions 45.v

The shell means 12 thus provides an expandable structure which is expandable vertically to substantially twice its collapsed size, and which provides an open structure enclosure with no lateral or longitudinal obstructions therein.

Accordingly, furniture, partitions or other similar structures can be conveniently provided in the lower shell portions 45 and the respective upper shell portions 46 can be pivotally expanded vertically with respect thereto without interference from such structures as may be desired and provided in the lower shell portions 45. In particular, FIG. 14 illustrates furnishings which may be provided in the lower shell portions 45, and specifically includes laterally extending seats 60, a table 61, and a lateral partition 62 which can be permanent and extend vertically upwardly to the top of the lower shell portions 46 if desired.

The roof assembly 13 is provided for, the other things, covering and retaining the shells 12 in the collapsed position (FIGS. 1 and 4); covering and retaining the shells 12 in the fully expanded position (FIG. 2); enclosing the space vacated by the shells 12 when the shells are extended with the secondary frame means 25 (FIGS. 3 and 7); and pivotally expanding the upper shell portions 46 with respect to the lower shell portions 45 (FIGS. 5, 6 and 13). The roof assembly 13, as illustrated herein, includes generally a roof panel 65 normally sup ported by the shell means 12, a pair of jacks 66 for vertically adjustably raising and positioning the roof panel 65, and a link means 64 for respectively pivotally interconnecting the upper shell portions 46 with the roof assembly 13. A vertical wall 67 is provided around the periphery of the roof panel 65 and a jack arm socket 68 is secured by a bracket 69 to the front and to the rear wall portions 67 of the roof panel 65. The jack 66 is adapted to be detachably mounted in apertures 70 in the tongue platform 19 and the rear step platform 20, and are each provided with first and second extending jack arms 71 and 72. The second jack arms 72 are adapted to respectively enter the sockets 68 when the first and second jack arms 71 and 72 are extended vertically upward by actuation of the jacks 66. The jacks will thereby raise the roof panel 65 to any selected position from the lower position (FIGS. 1, 4 and 12), to the uppermost position (FIG. 6). Although the jacks 66 illustrated herein are hydraulic jacks, it is to be understood that other types of jacks can be utilized without deviating from this aspect of the invention.

The link means 64 (FIGS. 4--6) for respectively intercon- I necting the roof assembly 13 with the upper shell portions 46,

whereby raising and lowering of the roof panel 55 will respectively provide vertical expansion and collapse of the shell means 12, comprises generally a pair of cables 75 secured to inner corners 76 of the upper shell portions 46 and operatively threaded over pairs of pulleys 77 rotatably mounted on a bracket 78 on the wall 67 roof panel 65, and thence connected by a clamp means 79 to the base frame 15.

When the structure 10 of this invention is in the collapsed condition (FIGS. 1, 4 and 12), the cables 75 will be in a slack condition as indicated (FIG. 4). This slack condition in the cables is provided to permit the roof panel 65 to be raised by the jacks 66 for a predetermined distance, taking the slack out of the cables 75 without movement of the upper shell portions 46 to provide clearance between the roof panel 65 and the upper shell portions 46.

When the roof panel 65 is thus sufficiently raised the predetermined clearance distance, and the cables 75 have become taunt, further raising of the roof panel 65 by jacks 66 will cause the upper shell portions 46 to be raised by the corners 76 thereof and pivoted about the respective hinges 58 with respect to the lower shell portions 45 as a result of the action of the cables 75 thereon.

It should be noted that as the upper shell portions 46 are thus expanded by raising the roof panel 65 after the predetermined clearance has been established between the roof panel 65 and the upper shell portions 46, that for every unit of distance the roof panel 65 is raised by the jacks 66, the corners 76 of the upper shell portions 46 will be raised two units. Therefore, the overall elevation distance required for the roof panel 65 to raise to expand the upper shell portions 46 upwardly to the uppermost position (FIG. 6), after the clearance distance is established, is only one-half of that which would be required if the roof panel 65 were connected directly to the upper shell portions 46 in lieu of the pulleys 77, etc.

When the upper shell portions 46 are expanded to the up permost position (FIGS. 2, 3, 6, 7 and 14), they are retained in that position by pins 80 inserted through apertures 81 in the upper shell portions and into similar apertures or over the top surface of the end panels 50 of the lower shells 45. After the pins 80 are inserted to retain the upper shell portions 46 in the up position with respect to the lower shell portions 45, the jack is actuated to lower the roof panel 65 onto the roof panel 55 of the upper shell portions 46 (FIG. 7).

The secondary frames 25 are then extended by rotating the cranks 41 as previously described, to extend the expanded shell means 12 to provide a space 85 therebetween. The shell means 12 are extended outwardly in this fashion until a longitudinal lip 86 (FIG. 16) extending upwardly from the roof panel 55 of the upper shell portion 46 engages the vertical wall portion 67 of the roof panel 65 or engages a weather stripping 87 therebetween. As the shell portions 12 are extended outwardly with the roof panel 65 in position thereon, lateral lips 88 (FIG. 16) provided on the ends of the upper shell portions 46 will move in recesses 89 formed in the sides of the vertical wall portion 67 of the roof panel 65. The lateral lips 88 provide longitudinal stability between the roof panel 65 and the upper shell portions 46 and provide horizontal extension beyond the lower shell portions 45 when the upper shell portions 46 are collapsed thereon (FIGS. 1 and 4) to provide a seal between the collapsed upper shell portions 46.

In the event that it is desirable to expand the structure of this invention toan intermediate form (FIG. 2), rather than the fully extended form (FIG. 3), as above described, the secondary frames 25 are retracted rather than extended after the upper shell portions 46 have been expanded to the upper position and retained (FIG. 6), as indicated previously, and before the roof panel 65 is lowered thereon as shown (FIG. 7). In particular, after the secondary frames 25 are fully retracted, the jacks 66 are actuated to lower the roof panel 65 onto and over the expanded shell portions 12 whereby the wall portions 67 of the roof panel 65 will engage the expanded upper shell portions 46, and the shell portions 45 and 46 will be covered by the roof panel 65 to provide the intermediate expanded form of the structure of this invention (FIG. 2).

Wall panels may form a part of the roof assembly 13 as well as part of the upper shell portions 46. In particular, wall panels 90, 91 and 92 are illustrated (FIG. 14) which are pivotally secured to the roof panel 65 of the roof assembly 13 by hinges 93 and are held in the up horizontal position by clamps 94 or other similar means secured to the roof panel 65 of the roof assembly 13 or an associated one of the wall panels 90, 91 or 92 pivoted to the horizontal up position above the panel to be retained thereby. Similarly, a wall panel 95 is illustrated (FIG. 14), which is pivotally secured to the roof panel 55 of the upper shell portion 46 by a hinge 96 and is held in the up horizontal position by a clamp 97 or other similar means secured to the roof panel 55.

Thus, the roof assembly wall panels 90, 91 and 92 will be retained within the roof panel 65 and shell wall panels such as 95 will be normally retained to the roof panel 55 of the upper shell portion 46 and will be releasable to pivot downwardly by 55 of the upper shell portion 46, may be released by clamp97l and pivoted downwardly to a vertical position to provide a vertical partition in the expanded shell means "12. The wall panel 95 can be positioned by the placement of the hinge 96 to align with the permanent partition 62 or other permanent structure in the space enclosed by the lower shellportion 45 as well as the partition when same is lowered.

Thus, it is illustrated that the structure 10 of this invention facilitates the provision of collapsible partitions 90--92 and contained within the roof panel 65 of the roof assembly 13 and the upper portion 46 of the shell means 12 respectively. without interfering with permanent structures such as seats 60, tables 61 or partitions 62 forming a permanent part of the lower shell portion 45. Also, the retractable partitions 90-92 and 95 thus provided provide a versatile structure wherein the partitions may remain up and open for ventilation if desired, or lowered into position to provide partitions and additional space enclosure for the occupants thereof.

Doors and windows, as shown generally, can be provided in the expandable shell means 12 or in the partitions as desired. Latches 98 (FIGS. 1-3 and 14) are provided which have roof panel latch elements 99 on the wall 67 of the roof panel 65, and which are adapted to interlock with shell latch elements 100 or 101 when the upper shell portions 46 are in the lower or expanded raised condition (FIGS. 1 and 12 and 3 and 13) respectively. The latches 98 thus provide a means for retaining the roof panel 65 on the upper shell portions 46.

It should be noted that the expandable structure 10 of this invention can be utilized as a trailer which, when collapsed, will provide a small and low lateral cross section configuration facilitating safety and convenience for operation on the highway. Further, the expandable structure of this invention provides a structure which can be expanded and collapsed by a single individual, and which, is capable of having the lower half ofits expandable height free from the structures and functions of expandabliity to facilitate the placement of permanent articles in the lower half thereof. Also, the structure of this invention provides retractable partitions in all sections thereof which are also completely free from the structures and functions of expandability. Further, the structure of this invention may be expanded or extended to various forms including an intermediate or fully expanded form as desire by the person or persons utilizing same.

It is to be understood that the invention is not to be limited to the specific constructions and arrangements shown and described, as it will be understood to those skilled in the art that certain changes may be made without departing from the principles of the invention.

What I claim is:

1. An expandable structure comprising a base frame assembly having a primary frame with secondary frame means horizontally extendible therefrom, said secondary frame means having a pair of secondary frames adjustably extendible from opposite sides of said primary base frame, vertically expandable shell enclosure means secured to said extendible secondary frame means for movement therewith from a given space to vacate and provide an upwardly enlarged space adjacent said shell means when said secondary fame is extended, said shell means comprising a pair of expandable lower shells respectively secured to said secondary frames and a pair of upper shells respectively pivotally secured to said lower shells to be pivotally vertically expandable therefrom, and a roof assembly for enclosing said space with said. shell means.

2. An expandable structure as defined in claim 1 wherein said lower shell portion has a vertical wall panel extending upwardly and longitudinally along said secondary frame means, said upper shell portion having a roof panel secured to one edge of an upper shell wall panel along a fixed dihedral and having said upper shell wall panel pivotally secured to an upper portion of said lower shell wall panel along the other edge of said upper shell wall panel whereby said upper shell portion is rigid and pivotable upwardly from a down position which encloses essentially the same space as said lower shell portion and away from said secondary frame and said lower shell portion to a vertically expanded up position to vertically expand said shell assembly frame.

3. An expandable structure as defined in claim 2 wherein a wall panel is pivotally secured to said upper shell roof panel and is pivotable downwardly therefrom and into said shell when said upper shell portion is pivoted to the up position to provide a vertical wall in said expandable shell.

4. An expandable structure as defined in claim 2 wherein a vertical wall panel is rigidly secured to said lower shell portion at a predetermined location and within said upper shell when said upper shell is in the down position, and a wall panel is pivotally secured to said upper shell roof panel and pivotable downwardly therefrom into engagement with sail lower shell vertical wall to provide a continuous wall therewith.

pivotable downwardly therefrom and into the vacated space to provide a vertical wall within said space.

7. An expandable structure as defined in claim 5 wherein said means for vertically adjustably positioning said roof panel comprises a jack means operatively interconnecting said primary frame and said roof panel.

8. An expandable structure as defined in claim 5 wherein link means interconnects said roof assembly and upper shell portions to pivot said upper shell portions upwardly in the expanded up position when said roof panel is raised.

9. An expandable structure as defined in claim 8 wherein said link means comprises a pulley rotatably secured to said roof panel and a cable operatively engaging said pulley and secured atone end to said primary frame and at the other end to said upper shell portion at a point away from the pivotal connection thereof with said lower shell portion whereby upward movement of said roof panel will pivot said upper shell to the expanded up position. 

1. An expandable structure comprising a base frame assembly having a primary frame with secondary frame means horizontally extendible therefrom, said secondary frame means having a pair of secondary frames adjustably extendible from opposite sides of said primary base frame, vertically expandable shell enclosure means secured to said extendible secondary frame means for movement therewith from a given space to vacate and provide an upwardly enlarged space adjacent said shell means when said secondary fame is extended, said shell means comprising a pair of expandable lower shells respectively secured to said secondary frames and a pair of upper shells respectively pivotally secured to said lower shells to be pivotally vertically expandable therefrom, and a roof assembly for enclosing said space with said shell means.
 2. An expandable structure as defined in claim 1 wherein said lower shell portion has a vertical wall panel extending upwardly and longitudinally along said secondary frame means, said upper shell portion having a roof panel secured to one edge of an upper shell wall panel along a fixed dihedral and having said upper shell wall panel pivotally secured to an upper portion of said lower shell wall panel along the other edge of said upper shell wall panel whereby said upper shell portion is rigid and pivotable upwardly from a down position which encloses essentially the same space as said lower shell portion and away from said secondary frame and said lower shell portion to a vertically expanded up position to vertically expand said shell assembly frame.
 3. An expandable structure as defined in claim 2 wherein a wall panel is pivotally secured to said upper shell roof panel and is pivotable downwardly therefrom and into said shell when said upper shell portion is pivoted to the up position to provide a vertical wall in said expandable shell.
 4. An expandable structure as defined in claim 2 wherein a vertical wall panel is rigidly secured to said lower shell portion at a predetermined location and within said upper shell when said upper shell is in the down position, and a wall panel is pivotally secured to said upper shell roof panel and pivotable downwardly therefrom into engagement with sail Lower shell vertical wall to provide a continuous wall therewith.
 5. An expandable structure as defined in claim 2 wherein said roof assembly comprises a horizontal roof panel normally supported by said shell means, and means for vertically adjustably raising and positioning said roof panel.
 6. An expandable structure as defined in claim 5 wherein an inner wall panel is pivotally secured to said roof panel and is pivotable downwardly therefrom and into the vacated space to provide a vertical wall within said space.
 7. An expandable structure as defined in claim 5 wherein said means for vertically adjustably positioning said roof panel comprises a jack means operatively interconnecting said primary frame and said roof panel.
 8. An expandable structure as defined in claim 5 wherein link means interconnects said roof assembly and upper shell portions to pivot said upper shell portions upwardly in the expanded up position when said roof panel is raised.
 9. An expandable structure as defined in claim 8 wherein said link means comprises a pulley rotatably secured to said roof panel and a cable operatively engaging said pulley and secured at one end to said primary frame and at the other end to said upper shell portion at a point away from the pivotal connection thereof with said lower shell portion whereby upward movement of said roof panel will pivot said upper shell to the expanded up position. 